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I’ve been exploring the capabilities of the Azure CLI recently and today I’m going to look at working with blob storage. To catch up on previous instalments check out these articles:

Creating a Storage Account

The first thing we want to do is create a storage account. We need to choose a “sku” – whether we need geo-redundant storage or not. I’m just creating the cheaper LRS tier in this example. I’m also making a new resource group first to put the storage account in.

$resourceGroup="MyStorageResourceGroup"
$location="westeurope"
$storageAccount="mystorageaccount"

# create our resource group
az group create -n $resourceGroup -l $location

# create a storage account
az storage account create -n $storageAccount -g $resourceGroup -l $location --sku Standard_LRS

Next, we need to get the connection string, which is needed for all operations on blobs and containers:

$connectionString=az storage account show-connection-string -n $storageAccount -g $resourceGroup --query connectionString -o tsv

A convenient feature of the CLI is that you can set the connection string as an environment variable to save having to pass the --connection-string parameter to every subsequent command.

Here’s how we do that in PowerShell:

$env:AZURE_STORAGE_CONNECTION_STRING = $connectionString

or if you’re in a bash shell:

export AZURE_STORAGE_CONNECTION_STRING=$connectionString

Creating Containers

Now we have a storage account, we can create some containers. The --public-access flag allows us to set their privacy level. The default is off for a private container, or you can set it to blob for public access to blobs. There’s also a container level which also allows people to list the contents of the container.

I’ll create a public and a private container:

az storage container create -n "public" --public-access blob
az storage container create -n "private" --public-access off

Uploading files

Uploading a file into your container is easy with the az storage blob upload command. You simply specify the name of the file to upload, the container to upload it into, and the name of the blob.

Here’s uploading a file into the public container and getting the URL from which it can be accessed:

# create a demo file
echo "Hello World" > example.txt

$blobName = "folder/public.txt"

# upload the demo file to the public container
az storage blob upload -c "public" -f "example.txt" -n $blobName

# get the URL of the blob
az storage blob url -c "public" -n $blobName -o tsv

If we upload a file to the private container, we’ll need to also generate a SAS token in order to download it via a URL. We do that with az storage blob generate-sas, passing in an expiry date and the access permissions (in our case, we just need r for read access).

$blobName = "folder/private.txt"

# upload the demo file to a private container
az storage blob upload -c "private" -f "example.txt" -n $blobName

# get the blob URL
$url = az storage blob url -c "private" -n $blobName -o tsv

# generate a read-only SAS token
$sas = az storage blob generate-sas -c "private" -n $blobName `
    --permissions r -o tsv `
    --expiry 2017-10-15T17:00Z

# launch a browser to access the file
Start-Process "$($url)?$($sas)"

More Blob Operations

Of course, there’s much more you can do with blobs from the Azure CLI, and you can explore the full range of options with az storage blob –h. You’ll see that we can easily download or delete blobs, snapshot them, as well as manage their metadata or even work with leases.

Of course, for ad-hoc storage tasks, Azure Storage Explorer is still a great tool, but if as part of a deployment or maintenance task you need to upload or download blobs from containers, the CLI is a great way to automate that process and ensure it is reliable and repeatable.

Want to learn more about the Azure CLI? Be sure to check out my Pluralsight course Azure CLI: Getting Started.
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